How to apply different styles to ui-autocomplete if more than one exist in a page

I have more than one JQuery autocomplete inputs in a page and i'm trying to give different style to them.

<div class="col-md-2">
    <?= $form->field($customermodel, 'name')->textInput(['maxlength' => true, 'autofocus' => true, 'class' => 'cdetails form-control customer-name']) ?>
</div>

<input type="text" id="select_itm" name="item[]" class="select_item">

I just tried out

.customer-name>.ui-autocomplete {
        cursor: pointer;
        position: absolute;
        height: 140px;
        width: 300px;
        overflow-y: scroll;
        overflow-x: hidden;
}
.select_item .ui-autocomplete {
        height: 100px;
        width: 300px;   
}

How can i apply separate style for the different input that use jquery autocomplete().